Refractometer help

[mihali]

Can I use Brightwell aquatics calibration solution if it’s not 25 degrees celcius

 

[FUNGI]

You should be able to if you have a ATC refractometer

 

[mihali]

I do

 

[mihali]

The refractometer is coming in a few days and I have the fluval hydrometer is that any good for now

 

[FUNGI]

From what I understand regarding ATC:
AUTO TEMPERATURE COMPENSATION (ATC)There is a lot of misunderstanding concerning the way the ATC feature worksand its effect on the refractometer at different ambient room temperatures.Salinity is a measurement of a mass of salt in a mass of water and thereforedoes not vary with temperature however a refractometer does not measuresalinity directly but measures the refractive index which is then displayed assalinity. The refractive index of a solution does vary with temperaturetherefore the reading that you measure with a refractometer is alwaystemperature dependant.An ATC refractometer has a bimetal strip inside the instrument that movesthe reading scale as the temperature changes to compensate for the changein refractive index.What people do not generally understand is that it is the temperature of theinstrument and not the water temperature that is important as the smallsample of water used for testing will equilibrate within seconds to thetemperature of the refractometer.

 

[FUNGI]

SOURCE: https://www.theaquariumsolution.com/sites/default/files/downloads/SEAWATER REFRACTOMETER V2.pdf

Its a pretty good read.

 

[FUNGI]

The refractometer is coming in a few days and I have the fluval hydrometer is that any good for now

You'll be ok with that for a general read until the refrac arrives...

 

[Randy Holmes-Farley]

I’ve never understood and do not agree with the assertion by manufacturers that the temp matters for an ATC refractometer calibration. I think they do not understand the implication of the purely mechanical temperature compensation that acts equally well on the standard as it does in the sample.

 

[mihali]

Are you saying temp doesn’t matter

 

[exnisstech]

Randy has a recipe for diy calibration fluid using table salt. I would trust it over a comercial product. The comercial product may or may not be accurate but if it isn't accurate your won't know unless you have something to compare it to.

Reef Aquarium Salinity: DIY Calibration Standards

Reef Aquarium Salinity: DIY Calibration Standards By Randy Holmes-Farley One of the most important issues facing marine aquarists is providing a suitable environment for their aquaria's inhabitants. Among the important properties for a marine...

www.reef2reef.com

 

[Randy Holmes-Farley]

Are you saying temp doesn’t matter

Within the range of the ATC temp correction, and if it works properly, yes, it does not matter.